I think I have successfully installed CUDA-7.5 on my computer, because I can actually run ./smokeParticles sample in NVIDIA_CUDA-7.5_Samples/bin/x86_64/linux/release/.

But I have one question:

How can I be sure that I'm actually using Tesla K40? Because the ./smokeParticles sample is also successful after I unplug the
Tesla K40 form my motherboard. (I assume that GTX 950 is running the sample...)